1. Field
Example embodiments relate to a gate structure, a method of forming a gate structure and a method of manufacturing a semiconductor device including a gate structure. More particularly, example embodiments relate to a gate structure including an upper portion having a width smaller than that of a lower portion, a method of forming the gate structure and a method of manufacturing a semiconductor device including the gate structure.
2. Description of the Related Art
Generally, a contact structure such as a contact plug penetrates an insulation interlayer interposed between a lower conductor and an upper conductor to electrically connect the lower and upper conductors to each other.
As the degree of integration of semiconductor devices continues to increase, the interconnect wiring width and or the spacing between the wirings becomes smaller. Thus, the spacing margin between the wiring and any contact plugs positioned between neighboring wiring segments is decreased.
As the distance between gate electrodes of a semiconductor device is decreased, the distance between a neighboring contact plug and a gate electrode is also decreased, and thus the problem of electrical shorting between the contact plug and the gate electrode is more likely to occur. In particular, contact plugs tend to widen at their upper portions. In this case, the width of an upper portion of the contact plug is greater than that of a lower portion of the contact plug, with the lower portion being connected to an impurity region formed in the substrate adjacent a gate electrode. Accordingly, an upper portion of the nearby gate electrode can inadvertently make contact with the neighboring contact plug more often than a lower portion of the gate electrode, causing a shorting problem.